Scrubbing machine

ABSTRACT

A scrubbing machine having a drive unit on which an operator can sit, and a separate scrubbing unit mounted for movement independently of the frame of the drive unit. The scrubber uses double brushes driven under power which will pick up debris from and scrub surfaces on which the unit is operating. The drive unit as shown operates on a dry surface because the scrubbing unit is trailing.

United States Patent Kasper Apr. 29, 1975 [5 SCRUBBING MACHINE 2.683.8857/1954 Johnson 15/83 x 3O54.l30 9/l962 Ferrari 15/340 [75] Inventor: 3Kasper 3.436.788 4/1969 Tamny .4 15/340 inn. 73 A T C M I I, FOREIGNPATENTS OR APPLICATIONS 1 ga ompany 678.194 [/1964 Canada 15/320 [22]Flledi 1972 Primary ExuminerEdward L. Roberts [211 App] No 299 824Altar/1e Agent or Firm-Dugger, Johnson &

' Westman Related U.S. Application Data [62] Division of Scr. No,72.275, Sept 15. W70. Pat. No, [57] ABSTRACT 7 A scrubbing machinehaving a drive unit on which an [52] U 8 Cl 15/50 5/320 [5/340 operatorcan sit, and a separate scrubbing unit [5 H 11/18 mounted for movementindependently of the frame of [58] Fie'ld C 5| 52 the drive unit. Thescrubber uses double brushes "ls/79 98 5 6 driven under power which willpick up debris from and scrub surfaces on which the unit is operating.The [56] Reterences Cited drive unit as shown operates on a dry surfacebecause the scrubbing unit is trailing UNITED STATES PATENTS 913,4602/1909 Bishop 3 15/340 Clams 22 Drawmg figures 7/ X I 1 I l '1' 1 111 111 1' ll' .1.

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WENTEE APR 2 9 ms SHEET 2 UP 9 SCRUBBING MACHINE CROSS-REFERENCE TORELATED APPLICATIONS This application is a divisional application of US.Ser. No. 72,275, filed Sept. I5, I970, now U.S. Pat. No. 3,702,488.

BACKGROUND OF THE INVENTION l. Field of the Invention The presentinvention has relation to self-propelled power driven scrubbingmachines.

2. Prior Art Various types of powered scrubbing machines have beenadvanced in the prior art, and some of them have utilized double brushscrubbing. A typical prior art machine having a double brush handoperated unit is shown in US. Pat. No. 3,061,859. U.S. Pat. No.1,694,937 shows another type of hand propelled floor scrubbing machineutilizing two scrub brushes.

Counterrotating double brushes have been used in street sweepingmachines, for example in US. Pat. No. 574,580. In US. Pat. No. 2,683,885a double brush floor cleaning machine having an operator seat thereon isshown. This machine is used for picking up liquids or other debris fromfloors and is not utilized with a scrubbing brushv A further floorcleaner is shown in US. Pat. No. 1,938,068 and this has double brushes,but the brushes are divided with an axially extending baffle whichlimits their effectiveness.

Many of these prior art devices are very difficult to manufacture, andoperate. For example, there is difficulty in steering or maneuvering thedevices, and when turning the squeegee or drying means utilized willtend to leave streaks or puddles. The devices are not quickly and easilytransported and do not adequately pick up debris. This means that thesurface usually has to be swept before scrubbing in the prior artmachines. Further, the scrubbing job has been incomplete, scrubbingliquid re-use poor, and the ability to get close to walls has been poor.

SUMMARY OF THE INVENTION The present invention relates to aself-propelled scrubbing machine that increases speed of operation,conserves scrubbing liquid and does not require sweeping of the floorbefore scrubbing because of the ability to pick up debris. The drive andsteering wheels are on a power unit of the vehicle, and a double brushwet scrubbing assembly forms a separate unit. The two units areconnected together with links to permit the unit carrying the scrubbingbrushes to be raised and lowered with respect to the power unit. Acontrolled floating action on the scrubbing unit is provided to controldown pressure on the scrubbing brushes.

The entire assembly is constructed so that the components utilized arearranged for balance, and the double brushes used with the scrubbingunit are properly positioned and of proper construction and size, andoperated at proper speed to pick up debris as well as scrub. The unitmay be thus used as a dry sweeper. The water or scrubbing liquid isreused by carrying it over the leading one of the brushes, and anyexcess water or scrubbing liquid carried by the trailing brush issqueegeed up and carried to a tank with a vacuum. A debris hopper orreceptacle is provided to receive debris and water or scrubbing liquidswept up by the scrubbing brushes. The debris hoppper may be mountedahead of the double brush unit, or to the rear of the double brush unit,as desired.

As shown, the two brushes are mounted so that they will scrub close tothe side edges of the machine, and the brushes are made so that they canbe removed for service by removing a bracket at one end of the brushes,and being pulled in this direction.

The frame member for the trailing unit includes a divider and guidebetween the brushes so that scrubbing liquid will be recirculated andreused, and debris will be guided into the debris receptacle.

Additional features include optional short turn devices for the driveunit and a sensing device to automatically remove some of the downwardload on the brushes when the power required to drive the brushesincreases, thereby providing automatic compensation so that the engineused with the unit is not overloaded.

If desired, the trailing unit can be mounted to move sideways so thatsharper turns may be made when the unit is adjacent the wall, andpositioning of the hydraulic reservoir used for supplying fluid to thefluid actuated drive components at the forward end of the drive andpower unit to counterbalance the trailing unit.

Two different size brushes may be used in the double brush scrubber forobtaining the desired control of the scrubbing operation.

A feature of the invention is that the power unit operates on a surfacethat has not been wetted by the sc rubber. In instances where the entiresurface has been flooded or is wet from external sources prior toscrubbing, the device may include means to deliver a drying air blast tothe wet surface immediately ahead of the drive and steering wheels.

The side squeegees used are mounted with leaf springs to permit them tofloat and still prevent escape of wash water and debris, even whenturning. The side squeegee leaf springs also automatically adjust forwear of the cylindrical brushes, so they dont have to be manually resetor adjusted. The rear squeegee cooperates with the side squeegees toprevent streaking in turning. A hydraulic cylinder controls up and downmovement of the rear squeegee so that it can be lifted upwardly whendesired to prevent damage, or forced downwardly with the desired amountof force.

The scrubber has variable speeds, is easy to steer and control, and ishighly versatile.

Objects of the invention are to provide a versatile scrubbing machinewhich has long life, good reuse of the scrubbing liquid, picks up debrisas it scrubs, variable speed, has ability to lift and lower thescrubbing unit, and provides the features described above and in thefollowing specification.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of ascrubbing machine made according to the present invention;

FIG. 2 is an enlarged side elevational view of the device of FIG. 1 withparts in section and parts broken away;

FIG. 3 is a fragmentary enlarged top plan view of a scrubbing unit ofthe present invention taken as on line 33 in FIG. 2;

FIG. 3A is a fragmentary perspective view showing a debris hopper beingremoved from the scrubbing unit of the present invention;

FIG. 3B is a fragmentary sectional view taken as on line 3B3B in FIG.3',

FIG. 4 is a side elevational view of the scrubbing unit with parts insection, and controls for a rear squeegee used shown partlyschematically;

FIG. 5 is a fragmentary side view of a side squeegee showing the leafspring mounting thereof;

FIG. 5A is a fragmentary sectional view taken as on line 5ASA in FIG. 5.

FIG. 6 is a schematic representation of the hydraulic circuit for thedevice of the present invention;

FIG. 6A is a schematic representation of a modification of the drivecircuit to aid in making sharper turns;

FIG. 7 is a part schematic side view of the trailing unit of the presentinvention showing a control for relieving the downward pressure on thescrubbing brushes in response to the torque required to drive thebrushes,

FIG. 8 is a fragmentary side sectional view showing a hopper dumpmechanism made according to the present invention;

FIG. 9 is a top plan view of the device of FIG. 8;

FIGS. 9A and 9B are a side and top view, respectively of a manualactuator for the hopper dump mechanism;

FIG. 10 is a schematic top plan view of a modified form of the inventionshowing a traversing trailer scrubber unit which permits sharper turnswhen the scrubber is adjacent to a wall;

FIG. 10A is a fragmentary rear view taken on line l0Al0A in FIG. 10;

FIG. 11 is a side view of a modified scrubber showing means for drying asurface that was wet prior to scrubbing;

FIG. 12 is a detailed view of a selector valve used when exhaust gasesare used for the drying air blast;

FIG. 13 is a view taken as on line l313 in FIG. 11;

FIG. 14 is a side view of a scrubbing unit modified to mount the maindebris hopper ahead of the brushes and also showing a second rearmounted hopper; and

FIG. 15 is a side view of a scrubbing unit showing brushes of differentsizes used for scrubbing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A scrubbing machine illustratedgenerally at 10 made up of a power and driving unit 11, and a scrubbingunit 12, which are independently constructed, and are connected togetherso that the power unit 11 will, as shown, pull the scrubbing unit 12over the surface to be scrubbed through a plurality of connecting linksillustrated generally at 13. The power unit comprises a main frame 14,powered drive wheels 15 at the rear thereof, and a front centralsteering wheel 16. This perhaps can be best seen in FIG. 6A. Each of thedrive wheels 15 is driven through a separate hydarulic motor 17 and 18,respectively, which are powered in a suitable manner through a variablevolume pump, as desired. The hydraulic motors are thus variable speedcontrolled, and a foot pedal 21 is used for controlling the speed of thevehicle by adjusting the variable volume pump.

The scrubbing drive unit can have brakes operated from a pedal 22 by anoperator sitting on the operator seat 23. The hydraulic motors l7 and 18can be mounted to the frame of the power unit independently, and thedrive wheels 15 are then drivably mounted on the respective outputshafts of the drive motors. Any

other suitable arrangement can be utilized for driving the vehicle inwell known manner.

The steering wheel 16 is mounted about an upright axis with a suitableframe 24, and is controlled from the operator steering wheel 25 througha drag link 26 and steering arm 27 shown in FIG. 6A. An automotive typesteering gear is used at the base end of the steering column.

The drive unit is powered with an air cooled engine illustratedgenerally at 30 located at the forward end of the power unit 11 andmounted onto the frame 14. The air cooled engine as shown is used forthe components, such as a main drive variable volume pump 29 (shown onlyschematically) and a hydraulic pump 31 for accessories, driven through abelt arrangement 32 from the engine output shaft. The pump 31 is usedfor powering the hydraulically driven components of the unit. As can beseen, a main hydraulic fluid reservoir 33 is at the front part of theframe 14.

The frame for the power unit also supports a clean scrubbing liquid tank34 on which the operator seat 23 is mounted, and as can be seen theclean liquid tank is hingedly attached to the frame so that it can betilted rearwardly as shown in dotted lines in FIG. 2 to permit access tocomponents positioned under the clean liquid tank. The battery, filterand other components can be housed under the clean liquid tank. Theclean scrubbing liquid tank is used for supplying water or otherscrubbing liquid, such as detergent or solvent solutions, to the surface35 over which the vehicle is moving and which will be scrubbed. Thismeans that there will be wet scrubbing. As shown, a hose 36 extends fromthe clean liquid tank downwardly to a transverse scrub liquid spreaderpipe 37 which extends across the width of the machine and is spacedslightly above the surface, and permits the scrubbing liquid indicatedat 38 to run out onto the floor and wet the surface ahead of thescrubbing unit 12. The pipe 37 of course may be of suitable type ofapplicator pipe, and these per se are well known in the art. The pipe 37comprises a liquid distribution header. The tube 36 includes a manuallyoperated on-off valve to control liquid flow. Clean liquid can besupplied to the liquid spreader pipe or nozzles under pressure orgravity feed.

The scrubbing unit 12, as shown, has a frame indicated generally at 41surrounding the scrubbing unit. This frame 41 is in turn reinforced witha cover frame plate 42 fixed thereto, and a transverse support anddivider baffle member 43 fixed to the plate to reinforce in plate (FIG.4). The frame 41, as shown, has a removable brace member 44 on one sidethereof removably joining front and rear cross members, and this bracemember may be removed (see FIGS. 3 and 4) to permit installation andremoval of a pair of scrubbing brushes 45 and 46. The forward or leadingscrubbing brush 45 is driven so that it rotates in direction asindicated by the arrow 47, and the rear or trailing scrubbing brush 46is driven as indicated by the arrow 48. The brushes are selected to havegood debris pick up characteristics. Thus the rows of bristles arespaced to permit the brushes to walk over debris. The brushes are notfull fill brushes. Further, the bristle rows are preferably of a herringbone pattern.

On the opposite end of the brushes from the removable brace, the drivemotors for the brushes are shown. These motors are fixed displacementhydraulic motors 51 and 52, respectively. The hydraulic motors arefastened through brackets 53 to the side of the frame 41 and the motorsextend inwardly so that the output shafts of each of the motors, forexample the drive shaft 52A shown for motor 52 is coaxial with therotational axis of its respective brush. As shown, the brushes areconstructed with an open tubular core member, as shown at SIB and 52B,and the bristles extend outwardly. The hydraulic motors fit within therespective tubular members. The shafts for the hydraulic motors havesuitable connections for connecting to mating adapter plugs shown at 56,in each of the respective brushes. The drive connections from thehydraulic motors are through the adapter plugs to the interior of thetubular members 518 and 528. The brushes are both supported by theirrespective motor shafts 52A and 51A, and also are driven by theseshafts.

The opposite end of the brushes are mounted on idler bearing plugassemblies attached to the brace member 44 which, as shown, fixedlymounts a pair of shafts 57 and 58, respectively. The shafts may bewelded to the brace member, if desired. These shafts 57 and 58 in turnhave suitably mounted bearings thereon which are merely idler bearings,and brush end adapter plugs 59 and 60, respectively, are mounted ontothe bearings so that the plugs will rotate freely with respect to theseshafts. The adapter plugs fit inside the tubular cores for the brushesand in turn have flanges which abut against the end surfaces of thetubular cores for the respective brushes 45 and 46. The plugs fit snuglywithin the interior cores. Thus when the brace member 44 is bolted inplace the frame 41 is held together, and the plugs 59 and 60 fit insidethe brushes to hold them in proper position relative to the frame and tothe drive motors. The brushes will rotate under power when theirrespective hydraulic motors 51 and 52 are powered. The brushes 46 and 45may be rotated at the same speed, or at different speeds. The higherspeed brush, if different speeds are used, is theone adjacent thehopper. Different speeds on the brushes may help in debris pick up(sweeping action) as well as liquid pick up. As an example of preferredoperation, brushes have an outer diameter of l 1% inches are operated atbetween 450 and 550 rpm. with both brushes at the same speed.

A door 61 is provided to cover the opening through which the brushes areremoved and serviced. A suitable hinge 62 is provided for this door.

The divider baffle 43 is a transverse member, as shown, and ispositioned above the two brushes 45 and 46.

In this form of the invention, as shown, a debris hopper illustratedgenerally at 65 is mounted. As shown, in FIGS. 3A and 3B, the debrishopper 65 is removably supported on provided ledges 41A formed by theframe 41, and has a lip portion 67 which is closely adjacent thebristles of the rear brush 46. The lip also is substantially along orslightly below a horizontal plane passing through the rotational axis ofthis brush. The frame plate member 42, as shown, ends along a rearwardedge that overlies the debris hopper, so any liquid thrown up by thebrushes and carried along the underside of the panel will drop off intothe debris hopper.

The debris hopper has a pair of handles 68 that can be used for manuallyremoving the hopper from the frame member for emptying when the hopperis full of debris.

Then, at the rear of the frame 14, and inside the frame, there is a rearsqueegee assembly illustrated generally at 70 which is controlled in upand down direction with a hydraulic cylinder 71, (FIG. 4) operatedthrough a valve of suitable design, as explained in connection with FIG.6. This squeegee assembly 70 is mounted on pivoting parallel arms 72, 72on opposite ends thereof so that when the unit is raised and loweredwith the hydraulic cylinder 71, it will raise parallel. Also as it wearsand is lowered, the squeegee will move straight down against the surfacerather than cock at an angle thereto. The squeegee has a top frame 73with upright members 73A to which the links 72 are pivotally mounted.The opposite ends of the links 72 are pivoted to the frame member 41.

The hydraulic cylinder 71 can be used to provide a down force on thesqueegee, and when the down force is overcome (a relief valve in valveHA is used for relieving this force) the squeegee will raise guided bythe parallel arms 72 against the down force of the relief valve.

As shown, the rear squeegee top frame member 73 has resilient,downwardly extending, spaced apart flaps 74 attached to frame 73. Theflaps can be made of a suitable elastomeric or other flexible materialthat will give slightly and provide a good drying seal against thesurface 35 to trap any liquid that gets past the scrubbing brushes andcollect it. The forward flap has a rib 74A that will engage the rearflap when the flaps are under vacuum to prevent the vacuum from beingclosed off from the ends of the squeegee. The flap has slots so liquidcan go between the flaps. The double brush assembly actually picks upmost of the scrubbing liquid in the hopper, and the rear squeegee insome instances can be lifted off the surface,

A vacuum fan illustrated schematically at 75 is mounted on the vehicleframe in a suitable location, and is driven with a hydraulic motor 75A.The suction line, shown schematically, is connected to a dirty liquidtank illustrated schematically at Z6 also mounted on the frame below theoperator's platform. This tank is closed and sealed with a plenumchamber at the top. The plenum chamber has a vacuum line 77 leadingtherefrom on the output side. Line 77 is above the liquid livel. Thevacuum hose 77 extends from the power and drive unit where the dirtyliquid tank is mounted, back to the scrubbing unit, underneath the frameplate member 42. The end of vacuum hose 77 has a Y connected pipeassembly 78 thereon. The Y pipe coming from the vacuum hose 77 is splitand has two vertical sections 78A and 788. Section 78A fits down insidethe debris receptacle or hopper 65. The vacuum pipe 78A just clears thefloor of the receptacle by a short distance and is surrounded by ascreen 79 (large size) that keeps out large pieces of debris, as shownin FIG. 38.

Pipe 78B extends downwardly through a provided recess in the debrisreceptacle or hopper 65, and is removably coupled with a slip coupling78D to a fixed pipe 78C which has a tapered end portion. The lower endof fixed pipe 78C fits between the rear flaps 74 to create a vacuum orsuction on the channel formed between the squeegee blade members. Thesqueegee flaps extend around the rear of the machine and then extendforwardly adjacent the sides of the machine to guide liquid toward thecenter of the machine. Thus the rear squeegee members collect the liquidfrom surface 35 that is left over from scrubbing. The liquid movestoward the rear center of the squeegee, enters the chamber between thefront and rear squeegee members, and then is vacuumed up through thepipe 78C, 78B and into the Y portion 78, tube 77 and back to the dirtyliquid tank. The liquid is collected in the dirty liquid tank. Likewise,any liquid that is carried into the receptacle or hopper 65 by the brush46 will be vacuumed up or sucked up through pipe 78A. A screen or grilleprotecting member is provided adjacent pipe 78A if desired to preventdebris from being picked up by the vacuum pipe 78A. The rib 74A preventsthe front flap 74 from collapsing and cutting off vacuum from the endsof the squeegee.

In addition to the rear squeegee assembly, there are squeegees providedalong the sides of the scrubbing unit. As shown in FIG. 3, there is asqueegee assembly 80 along the right hand side of the unit which isfastened to the frame member 41, and a squeegee 81 which is along theleft hand side of the unit and this squeegee is fastened to the covermember 61 so that it moves with the cover member. Both the squeegee 80and 81 are provided with end portions 80A and 81A, as shown in FIG. 3,that go on the inside or forward edge of the forwardly extending endportions of the rear squeegee 70. The scrubbing liquid collected alongthe side squeegees is thus guided to the rear squeegee and furtherguided toward the center thereof for pick up.

The squeegees are mounted in a unique manner, as shown in FIG. 5. Theside squeegees each comprise upper frames 82 and they are mounted onleaf springs 83 which are attached to the frames 82, and to some portionof the main frame 41. In the case of squeegee 81, it is attached to thedoor 61. The leaf springs permit the flexible skirt portion 84 of thesqueegee which is attached to the frames 82 to move laterally over thefloor and to give slightly sideways, and also move up and down in alinear direction without causing the squeegee to twist, rub extensivelyand wear out.

The leaf springs further provide some give" when the unit swingssideways during turning, as a trailing unit will, and provide forautomatic adjustment for wear of the brushes. The leaf or blade springsgive to compensate for this wear without manual adjustment.

Small brushes 85 are attached to the frames 82 and are positioned alongside the main brushes and are row brushes. The side squeegee members areformed so that the flexible sections 84 extend outwardly at an anglewith respect to the support 82. The flexible sec tions extend outwardly,as shown in FIG. A, and the brushes 85, which are attached to the upperframes 82, extend inwardly toward the main rotary brushes 45 and 46. Thesmall brushes 85 are positioned to engage the surface being swept, aswell as being very close to the end bristles of the main rotary brushes45 and 46. This action keeps the debris from being spilled out aroundthe ends of the main brushes and also prevents the debris from beinglost from between the brushes 45 and 46 underneath the squeegees whenthe corners are being turned and the rotary brushes slide sideways.

The outwardly extending flexible sections on the squeegee will insurethat the side portions are kept free of debris and also the scrubbingliquid is kept inside the unit. The outward extension of the flexiblesection makes it easier for the flexible sections 84 to be in contactwith the surface 35 where the flexible members on the side squeegeesangle inwardly to be inside the rear squeegee as shown in 80A and 81A.This outwardly extending slant of the flexible section also permits themto follow the surface 35 when corners are being turned without turningunder and getting out of position. When the vehicle is turned thesqueegees have to slide sideways a substantial amount. The straightflexible members tend to fold in or out and when this happens, thesqueegees would fold out of position and no longer give a good seal. Theoutward slant of flexible members prevents this.

The scrubbing unit is attached to the power unit in an independentmanner. While rear mounting is shown, the unit may be front mounted andpushed rather than pulled. The improvements described in the scrubbingunit are very beneficial whether the unit is front or rear mounted, butrear mounting permits the power unit 11 to operate on a dry surface. Thelinks shown generally at 13 are shown in greater detail in FIGS. 2, 3and 4. As can be seen, a pair of spaced apart channel members 87 arefixed to the top plate member 42 of the frame 41 and extend upwardlytherefrom to form a control mast assembly. It should be noted that thesechannel members are positioned substantially directly above the crossframe member 43 that extends transversely across the frame.

The channel members 87 in turn have a channel shaped main tow and liftlink 88 pivotally between them with a pin 89. The pin 89 extends along atransverse axis. The link 88 as shown, is not straight, but has a bendin it for clearance purposes, and the opposite end of the link 88 ispivotally attached with a pin 90 to a provided mounting portion of theframe 14 of the power unit. In addition, the scrubbing unit is connectedto the power unit with a pair of spaced apart outboard drag links 91 and92, respectively, which have suitable part spherical seat pivoting rodends thereon. First ends of the drag links are attached to suitable ears93 on the main frame of the power unit 11, and the opposite ends oflinks 91 and 92 are attached to suitable ears 94 on the frame platemember 42 of the scrubbing unit. These drag links keep the scrubbingunit properly positioned as it is being towed through the main pull link88, and also control the angle of the scrubbing unit with respect to thesurface 35 as the scrubbing unit is raised.

The support for the scrubbing unit comes through link 88, and this linkcan twist and give to permit one end of the scrubbing unit to raiserelative to the other as it moves over irregularities. The links 91 and92 permit this movement.

Raising and lowering of the scrubbing unit is controlled with ahydraulic cylinder 95, which can be single acting because it only has tolift the scrubbing unit, and the weight of the scrubbing unit will causeit to retract, and this hydraulic cylinder 95 is attached as at 96 tothe main frame of the power unit. The cylinder 95 has an extendable andretractable rod 97 pivotally attached as at 98 to the link 88.

Thus, when the power unit is powered and moving over the surface, thelink 88 will pull the scrubbing unit along, and the links 91 and 92 willalso keep the scrubbing unit properly positioned and exert a pull on it,while permitting the unit to float over objects, if necessary.

As can be seen in FIG. 2 in dotted lines, the trailing unit can beraised. The drag links 91 and 92 control the angle of the scrubbing unitwith respect to the surface when the scrubbing unit is lifted. When thepull link 88 is raised to its dotted line position, it can be seen thatthe rear portions of the scrubbing unit raise much higher than theforward portions to provide for clearance at the rear if the vehicle isdriven up an inclined surface.

A safety lock member 100 is pivotally mounted about the same pin 98 asthe rod of the hydraulic cylinder, between the legs of the link 88, andis controlled through a push pull control wire 101 which is similar toan ordinary choke control. The control wire can be moved to its solidline position as shown in FIG. 2, and then the cylinder 95 will beoperable and can be retracted when the control valve for the cylinder isoperated. However, when the cylinder 95 is extended, the control 101 canbe pushed to its dotted line position by an operator and this will movethe safety lock member 100 into position as shown in dotted lines wherethe end of the member 100 will abut against the end surface of thecylinder itself around the rod, and prevent the rod from retracting.This will hold the scrubber unit raised even if hydraulic pressureshould fail, as a safety measure. The scrubbing unit is raised and maybe locked in raised position for rapid transport without having thebrushes and squeegees wearing against the surface 35.

The control line leading to the cylinder 95 can have a suitable valveassembly shown schematically at 102, which can be adjusted so that onlya desired amount of lift pressure will be exerted on the cylinder 95.This will mean that the operator can vary the load supported by thecylinder 95 so that the downward bearing pressure of the scrubbing uniton the brushes 45 and 46 can be changed by adjusting the valve to changethe size of a bypass orifice and thus change the pressure in the line104 and cause the cylinder 95 to bear more of the weight of thescrubbing unit. It should also be noted that a flow divider 105, whichis shown schematically, divides the flow from the pump 31 so that a lowflow, for exmaple 1 gallon a minute, will be flowing through the valve102. Then, even if the engine 30 drops in r.p.m. so the output of thepump drops, this small flow will be maintained, and the cylinder 95 willnot suddenly drop because of a reduction flow through the control valve102.

A feature of the unit is that the forward housing 108 over the enginehas a center opening 109, that has a sealing member 110 that matesagainst the outer periphery of the inlet opening to the provided enginecooling fan so that there is no possibility for air to be drawn fromaround the interior of the housing 108 into the engine and fresh cleanair will always be blown across the engine. The engine is a conventionalair cooled engine. The warm air can be disbursed out through suitableducts.

Additionally, the carburetor for the engine can be mounted so that ithas its intake open directly to the air cooling housing for the enginefan so that there is a fresh flow of air coming through opening 109 intothe carburetor which slightly super charges the engine. The engine coverhaving opening 109 of course can be removed for servicing.

A sheet metal housing 107 can be used over the scrubbing unit. Thehousing 107 may also be plastic if desired, and has a movable covermember 107A that is hinged to the main part of the housing 107 and canbe raised and lowered to get into the debris hopper, and remove it forcleaning or to service components in the scrubbing unit. This cover isshown in its dotted position in FIG. 1. The cover 107A when fasteneddown with suitable clamp means, holds the debris hopper in properposition.

FIG. 6 is a hydraulic schematic representation of the drive componentsof the present invention. It was previously mentioned that the unit usedtwo different hydraulic pumps, and these pumps are shown schematically.The engine 30 drives the hydraulic pump 31 which is the hydraulic pumpfor auxiliary components, and the engine also drives a variabledisplacement piston type pump 29 which is used for driving the wheelmotors l7 and 18 in a closed circuit. The variable displacement pump isa commercially available pump that has a lever control operated by footpedal 21 that regulates the amount of oil that is pumped, and the amountof oil being pumped through the motors 17 and 18, which, as shown, arein parallel, determines the speed of movement of the vehicle. A suitablehydraulic makeup circuit 28 can be installed in this circuit to takecare of any leakage losses and the like. The makeup circuit is a commoncircuit furnished with the pump, which is made and sold by VickersMobile Division of Sperry Rand Corporation. The pump has a swash platecontrol to regulate the amount of fluid under pressure being pumped outinto the motors 17 and 18. The pump is an over-center pump that mayprovide reverse flow to the motors and thereby reverse rotation of themotors as well as provide a neutral or stopped position. The pump 31 hasthe flow divider 105 built into the pump and this delivers a set lowvolume, for example gallon a minute, at 1,000 pounds per square inchpressure to the hydraulic cylinder for the control of lifting andlowering the trailing unit. The valve assembly 102 includes a manuallycontrollable spool shown at 102A that can be shifted from a centralposition wherein flow from the flow divider will merely pass through thevalve and out into a return line 103 but do this through a variableorifice valve 102B that controls the amount of back pressure in thelines leading from the flow divider 105. A relief valve 102C is alsoprovided across the line to relieve overpressures.

When the valve 102A is shifted to position wherein the side indicated at102D is aligned with line 104, it can be seen that fluid under pressurewill be applied to the hydraulic cylinder 95, but only the amount ofpressure that the adjustable valve 1028 provides as a back pressure.This then actuates the rod 97 of the cylinder at a selected manuallyvariable pressure so that the downward load on the brushes in thescrubbing unit can be regulated by adjusting the valve 10213. When thespool is moved in the opposite direction so that the section 102E alignswith the line 104, the full pressure of the relief valve setting ofvalve 102 can be applied to the cylinder 95, and positively raise thescrubbing unit. This means that the scrubbing unit can thus be held inan upright position, and when the valve spool 102A is again returned toits centered position as shown in solid lines, the line 104 is blockedin the central portion of the valve and the flow from the flow divider105 is directed through the spool into the series circuit through line103.

The cylinder 71 for the rear squeegee assembly 70 is connected through avalve 71A to the line 103. This valve or cylinder 71 is a double actingcylinder and the spool valve 71A is a normal fourway valve which willblock both lines leading to the cylinder 71 in its central position, andwill in one position force the rod of cylinder 71 out and in the otherposition force the rod of cylinder 71 in. The unit is normally operatedwith the valve set to force the rod outwardly. A suitable relief valveis also supplied in valve 71A and is set to open when the pressureurging the rod of cylinder 71 out exceeds a preselected amount. Therelief valve setting in valve 71A thus determines the force applied tothe rear squeegee and is usually set very low, for example 50 p.s.1.

The various valves are connected to drain or reservoir through linesshown schematically to the reservoir 33 which is also shownschematically.

The balance of the output of the auxiliary pump 31 comprises a highervolume of flow, for example a flow of 7 gallons per minute at ratedspeed for the pump 31. This secondary flow is in a circuit driving thebrushes and the vacuum fan. The flow divider 105 has priority, so evenwhen the motor 31 is running at low speeds, the 1 gallon per minute willbe delivered to make the adjustable valve 1028 effective to hold thetrailing unit at the desired force level. This l gallon per minute is aconstant flow even though the engine 30 may be idling, so that thesetting of adjustable orifice valve 1028 can be held constant.

The pump 31 in a normal situation is used for driving the brush motorsand the fan motor in a series hydraulic circuit. A control valve 113 isused, and in its centered position it will merely return the flow fromthe pump 31 on the secondary side indicated at line 114 to the reservoir33. However, when it is shifted to position so that the section 113A isaligned with the center connecting pipes, it can be seen that the branchline 114A will be directed toward a blocked port 1148. The output of thepump 31 on the secondary side is then directed to the motor 51, then tomotor 52, and then to the motor 75A for the vacuum fan in series. Theother side of the motor 75A then returns to the reservoir. This is thenormal operation where all of the motors are operating at once,including the scrubbing brushes, and the vacuum fan motor.

When the valve 113 is shifted so the portion 1138 is aligned with thecenter section, it provides a means for stopping the brush motors 51 and52 and operating the vacuum fan motor 75A alone. This may be a situationwhere scrubbing is not desired, but vacuum is wanted, for example, forpicking up of liquid in a stationary position or even picking up liquidwith the squeegees as the unit moves over a surface. In this instance,the branch line 114 directs the fluid under pressure through a checkvalve 115 into a line 116 that intercepts the series connected linebetween motor 52 and motor 75A, and supplies fluid under pressure tothis point. Because this pressure will be equal to that on the line 114through the motors 51 and 52, the motors 51 and 52 will not rotate butwill maybe stand still, and the entire output of the pump 31 on thesecondary side will be directed through line 116 to motor 75A and drivethis vacuum fan motor. The valve 113 can again be returned to neutralwhen the unit is merely idling and not being used at all.

A low pressure bypass valve is used in the return line coming from thevalves 102 and 71A to bypass a filter shown in the return line when thefilter back pressure exceeds this setting.

Thus, the wheel drive circuit is separate from the accessory circuit andthe variable volume pump takes care of just the wheel motors, and thesetting of the pump determines the speed at which the motors operate.The setting of the pump can be actuated through the pedal 21 to operatea swash plate. The pump 29 also drives the unit in reverse.

The accessory pump 31 has a priority circuit through flow divider 105that goes to a cylinder first so that the float on the rear unit can beadjusted accurately by adjusting the variable valve 1028. The unit isthus all hydraulically driven in its accessory and ground drivecircuits.

In operation, the unit is steered through the use of the front steeringwheel. The unit can be moved to scrub within one and a half inches of avertical side wall and will turn corners in a usual manner.

The scrubbing liquid tank has a valve that can be opened so that thescrubbing liquid carries out through openings in the spreader pipe orheader 37, and the hydraulic motors for the scrubbing brushes 45 and 46are activated to rotate the scrubbing brushes 45 and 46 in thedirections as indicated by the arrows for the respecitve brushes. Thepower unit will then be driven forwardly and debris on the surface 35will be picked up by the leading brush, carried up by the second brushbetween the two brushes together with the scrubbing liquid that hascontacted the surface and a scrubbing action will take place. Scrubliquid is reused by diverting some of the liquid over the front brushand back onto the floor. The frame divider member 43 will divide theflow of liquid and direct the debris backward into the debris hopper. Itshould be noted that the divider frame member 43 is positioned so thatit is closer to the leading brush adjacent the top parts thereof andthis causes debris to be deflected along the trailing surfaces of thisframe member and over the trailing brush back into the rear debrishopper. Liquid will be carried forwardly over the bristles of the frontbrush 46 and will be reused or applied to the surface 35 as the scrubbing action takes place. Liquid collecting on the divider frame member43 and along the underside of the plate 42 will drip off the edge of theframe member back into the forward brush and be carried over this brush.Some of the liquid will be carried back by the rear brush 46 into thedebris hopper, which is very close to the brush bristles, and thisliquid will be sucked into the dirty liquid tank through hose connection78A.

Liquid that remains on the surface 35 will be gathered in by thesqueegees as the scrubbing unit moves forwardly and will be trappedbetween the flexible members 74, 74 and sucked by the pipe 78C throughpipe 788 and into the dirty liquid tank as well.

Thus the surface is swept and scrubbed clean and left dry. The scrubbingunit also may be used as a double brush mobile sweeper, merely byturning off the flow of liquid in spreader pipe 37. With the brushesrunning they will pick up dust and debris and deposit it in the debrishopper as the unit moves over the surface. The rear squeegee can beraised and the vacuum can be used for dust control, if desired.

The speed of the scrubbing brushes, the relative size of the twoscrubbing brushes, the spacing between the brushes, and the travel speedof the unit are all interrelated in doing a good scrubbing or sweepingjob. Brush peripheral speeds should be above l feet per min- Hi6.

The use of two brushes traveling at the same speed tends to throw theliquid and debris almost straight up. The deflectors or guides used thendetermine the direction of movement of the liquid and debris. If onebrush rotates faster than the other and both are the same size, thedebris will be deflected at an angle toward the slower brush. If twodifferent size brushes are used, the larger brush deflects the debris atan angle over the smaller brush. Thus, speed and size of the brushes canbe selected to obtain the desired trajectory of liquid and debris whilescrubbing. The brushes are preferably close together, but can be spacedfor debris pick up. The close spacing is helpful for liquid and finedust pick Driving 1 1% inch diameter brushes between 450 and 550 rpm.gives a good balance between ability to pick up dust, dirt, liquid anddebris and prevents atomizing or misting of liquid because of too high aspeed, which mainly consumes horsepower. In other words, if the brushesare traveling at a very high rate of speed, the scrub liquid tends tomist, and the consumption of horsepower goes way up in relation to theability to scrub and sweep.

A further point in recirculation of scrubbing liquid is that the dividerbaffle member 43 is positioned so that the tip of it is above theforward brush in the first form of the invention so that the scrubbingliquid is recirculated. The liquid will drip off the tip of the edgedown on the brush and be recirculated. This is a desirable feature, andof course the positioning of the center baffle therefore is important sothat the tip or edge that extends parallel to the axis of rotation ofthe brush is above the brush bristles and scrub liquid dripping off thistip or edge will be dropped back onto the recirculating brush, which inthis instance is the forward brush 45. If a forwardly mounted unit isutilized, recirculation of liquid can be achieved by having suitablemeans in the debris hopper for recirculating some of the liquid.

In FIG. 7 a modified automatic arrangement for controlling the downpressure on the scrubbing brushes is shown. In this device, the brushes45 and 46 are mounted in the frame as before, and the hydraulic motors51 and 52 are shown mounted to the frame structure 41. In this instance,the hydraulic pump is shown schematically and supplies pressure to thecylinder 95 acting on the link. In this instance, the input line to thecylinder is line 150 connected to a suitable control valve shownschematically at 151, which also controls the flow to the brush drivemotors 51 and 52 through a line 152. As shown, the motors 51 and 52 arehydraulically coupled in series. A cylinder tap off line 153 isconnected to the line between the two motors 51 and 52, and operatesthrough a check valve 154 to connect to the line 150. A small fixedrestriction orifice 154A limits flow into line 150 through the checkvalve. The adjustable flow restriction valve 155 (a variable flow valvewhich is manually operable) is utilized. In normal operation the valve151 is moved to position wherein flow goes from the pump to line 152through motor 51, driving it, and then to motor 52, and then back to thereservoir. The pressure of the motor 52 acts through bleed off line 153causing the flow through check valve 154 and restruction orifice 154A.Flow back to the reservoir through line 150 is restricted to a setamount because of the adjustment of the variable restriction valve 155.The back pressure thus acts on cylinder 95 and acts to exert a liftingforce on the trailing unit.

If the load on the motor 52 increases because of heavier brushing, theincreased pressure in line 153 will act through the check valve 154 toincrease the pressure in line 150 on the base end of the cylinder 95 andthus tend to increase the force bearing on link 88. This will tend tolift the scrubbing unit 12, and will in turn reduce the downward load onthe brushes and consequently reduce the power necessary to drive thebrush motors. A balanced condition will be reached to maintain the loadon the motors 51 and 52 below a maximum. There is therefore an automaticreduction of the load on the brushes when the pressures that operate themotor 52 increases to a point beyond that which the normal pressure inline 150 would be. The check valve 154, of course, prevents flow fromthe line 150 into the motor circuit. In this instance, if the scrubbingunit is to be lifted for transport, the valve 151 can be moved toposition wherein the pump is coupled to line 150. The pressure will thenact to extend the cylinder rod for cylinder and raise the scrubbingunit.

Automatic compensation to prevent killing of the engine 30 is providedbecause the load on the pump shown schematically will be regulated inaccordance with the load on the scrubbing brushes.

Referring to FIGS. 8 and 9, a modified form of the debris hopper isshown. In FIG. 8, the trailing unit 12 is modified so that the frame 41mounts a transverse rear baffle panel that is fixed to the frameadjacent the upper rear parts thereof, and extends downwardly andforwardly and is attached between the side members of the frame. Thebaffle forms a rear wall of the debris hopper indicated generally at 126positioned behind the rear brush 46. The debris hopper includes atransversely extending front panel 127 that is attached between the sidemember of frame 41 and is positioned just immediately to the rear of therear brush 46. Al though the vacuum hose is not shown, the vacuum hosewill be used with this hopper as well.

A movable bottom panel 128 is utilized for the hopper, and this is dustsealed along the front and rear edges with respect to the rear panel 125and the front panel 127. The bottom panel 128 is mounted on a centrallymounted rod 129 which is pivotally mounted to a suitable ear 130 on thebottom panel, and also is pivotally mounted to a projecting support 131fixed to the rear panel 125. The link or rod 129 holds the bottom panelin the proper position when the panel is in its solid line position asshown in FIG. 8. The position of the false bottom panel 128 iscontrolled through a pair of spaced apart links 134 that are pivotallymounted to space support ears 135 fixed adjacent the front edge of thebottom panel 128 and is also mounted onto the outwardly extending endspaced levers 136 of a bell crank assembly. The levers are fixed to arock shaft 137 that is pivotally mounted to frame members on the rearframe portions of the trailing unit 12. The rock shaft also includes acentral control lever 137A fixed to the rock shaft. The lever 137A isattached as at 138 to the outer end of the rod 139 on a hydraulicpiston-cylinder assembly 140. The base end of the cylinder of thisassembly 140 is mounted as at 141 to the frame for the trailing unit 12.

The cylinder assembly 140 can be extended and retracted through asuitable control valve 144 that actuates the cylinder from a source ofpressure. When the cylinder is extended, as shown in solid lines in FIG.8, the levers are in their solid line position and the links 134 forcethe false bottom 128 downwardly to close the opening between the frontpanel 127 and rear panel 125. This means that any debris coming from thebrush 46 will be trapped and held in the hopper, and also the scrubbingliquid will be collected and removed with the vacuum line as previouslyexplained.

When the debris hopper fills, however, the false bottom panel 128provides a means for emptying the dcbris hopper without manually liftingit out as previously shown in FIG. 3A. In order to do this, the valve144 is actuated to retract the cylinder 140 to its retracted positionshown in dotted lines, which will in turn lift the levers as shown indotted lines, and this will cause the bottom panel to pivot about theconnection between the links 129 and brackets 130 and also then willpull up the forward edge of the panel 128 so that the panel 128 willtilt upwardly as shown in dotted lines in FIG. 8. The link 129 will alsopivot about its connection to the supports 131 and will hold the rearedge of the bottom panel downwardly so that the bottom panel 128 extendsalmost substantially perpendicular to the surface being traversedcausing complete dumping of any debris in the hopper, without removingthe hopper itself. The use of the raisable rear squeegee assemblies thusis very important here because the squeegee can be lifted up over thedebris when the scrubbing unit is driven forwardly. This device fordumping also can be used where the main debris receptacle is ahead ofthe brushes, as shown in FIG. 14.

As an alternative, shown in FIGS. 9A and 9B, in place of the hydrauliccylinder 140, a manual lever 145 can be pivotally mounted as at 146 to aposition of the frame for the trailing unit 12 and a link 147 extendsbackward to the trailing unit and is attached to point 138 to the rockshaft lever. Movement of the manual lever by the operator will cause thesame action as the hydraulic cylinder retracting. This will cause themovable bottom 128 to dump and it can be done manually. This is just analternate method of manual operation as opposed to power actuatedoperation which occurs with the cylinder 140.

FIGS. 10 and 10A are schematic showings of a mounting for the scrubbingunit 12 with respect to the power unit 11 so that the scrubbing unit canbe moved laterally from side to side if desired to give more sideclearance when sharp turns are made in either direction with the powerunit 11. This is shown schematically for purposes of illustration, andit is to be understood that the steering and drive mechanism for thepower unit 11 will be the same as previously disclosed. The mounting forthe scrubbing unit is modified so that the link 88 is replaced with alink 160 that is similar to the link 88 except it has an outwardlyextending end tab 161. In place of the pin and upright channels 87, thetrailing unit has a pair of upright posts 162, 162 mounted thereon whichare spaced apart a substantial distance and are wider than the link 160.The upright posts are fixed to the cross frame plate 42 and aresufficiently sturdy and reinforced so that they will support the entireweight of the scrubbing unit 12. A cross shaft 163 is fixedly mounted(it can be removable if desired) between the posts 162, 162 and extendsthrough the downwardly depending legs of the bracket 160 as the pin 89extends through the legs of the bracket 88. However. the shaft 163 isslidably mounted in suitable hubs along the legs of the bracket 160.

The position of the scrubbing unit along the longitudinal axis of theshaft 163 is controlled with a double acting hydraulic cylinder 164 thatis attached as at 165 to the outer end 161 of the link 160, and thecylinder 164 has an extendable and retractable rod 166 that is attachedat 167 to a bracket that extends upwardly from the base of unit 12 sothat the cylinder is in proper alignment. The cylinder 164 may becontrolled through a suitable valve 168 from a pump and reservoir is theusual manner, and it is a double acting cylinder. The links 91 and 92 aspreviously explained, have rod ends at their outer ends where theyattach to the frame work of the trailing unit 12 and these rod ends havepart spherical seats of conventional design in the present form of theinvention shown in FIGS. 10 and 10A. The entire scrubbing unit 12 can bemoved axially along shaft 163 by either extending or retracting thecylinder 164. In normal operation the side edge of the trailing unitindicated at 171 is offset from the main part of the vehicle so that itwill travel next to a wall while the power unit is spaced from the wall.In turning away from the wall the cylinder 164 is operated so the edge17] is moved away from the wall so both side edges 170 and 171 of thescrubbing unit are flush with the edges of the power and drive unit. Asharp turn can be made because the scrubbing unit will not immediatelyengage the wall but will give some room for starting the turn before itgets close to the wall. Also, the offset keeps the power unit away fromthe wall for easier maneuver By properly controlling the cylinder 164,the scrubbing unit can be slid axially along the shaft 163 to accomplishthe desired positioning. The offsettable features are desirable whetherthe scrubber is from or rear mounted. The unit may be operated with thescrubbing unit in its dotted line position with edges 170 and 171aligned with the edges of the power unit.

The cylinder 164 may also be automatically actuated by a solenoid valve156 operated by switches 1S7 actuated by the vehicle steering arm 27after the arm has been moved a preselected amount in either direction.

Switches 158 along the sides of the trailing unit also could be used tocontrol a solenoid valve 159 so that if the trailing unit rubbed againsta side wall surface, the cylinder 164 would be actuated to move thetrailing unit in proper direction away from the wall.

Referring now to FIG. 6A, a further modification of the device of thepresent invention, which is used for making sharp turns is disclosed.Here the power unit 11 has wheels, and drive motors l7 and 18, as wellas the steering assembly arm 27. The motors l7 and 18 are normally inparallel, and both operate in the same direction. A reversing valve 175is connected to permit normal parallel operation with both motorsturning in the same direction or with one rotating in reverse from theother. The reversing valve is shown in reverse position. The valve 175is controlled by a solenoid 176 to its reverse position so motors 17 and18 rotate in opposite directions. When the scrubbing machine is to beturned in direction as indicated by the arrow 177, a switch 178 iscontacted by the outer end of the steering arm 27 when the arm reachesits full turn position which will energize the solenoid 176 to move thevalve 175 to its reverse position as shown, thus making the machine turnmuch sharper because of the reverse driving action of the two wheels.Opposite direction reversal is possible by having another switch (notshown) that is engaged by the steering arm 27 when the wheel forsteering is turned in the opposite direction. By reversing the flow tothe wheel motors l7 and 18, these sharper turns can easily beaccomplished. Normally.

17 the motors operate from the straight through position of valve 175.

in FIGS. 11, 12 and 13, there is a device shown which is used to directa blast of drying air or gaseous medium onto the surface 35 as shown. Inone form, the engine 30 is an internal combustion engine and the driveshaft is connected through an engageable-disengageable (clutched) beltdrive shown schematically at 190 to a centrifugal fan 19] which has apressure outlet 192. This pressure outlet is connected through a pipe193 to a cross pipe 194. The cross pipe 194 has downwardly extendingpipe sections 195 and 196 that are positioned in front of each of thedrive wheels 15 of the power unit. The downwardly extending pipes 195and 196 end in flat broad nozzles 195A and 196A, respec tively, that arepositioned closely adjacent surface 35 and immediately ahead of therespective wheel 15 to direct a jet of air down onto the surface andblow any liquid on the surface 35 out of the way, as well as create asurface drying action because of the moving air.

At the forward end of the power unit 12, on the steering member, thepipe 192 is connected to a flexible hose 197. A downwardly extendingpipe 198 then is attached to the mounting frame for the wheel 16, whichsteers and of course moves, so that this downwardly extending pipe 198moves with the wheel. Pipe 198 has a nozzle 198A that is also flattenedout slightly and is directed immediately in front of the steering wheel.The steering wheel 16 is thus also provided with a dry path immediatelyahead of the wheel, even though it may be turned from its straight aheadposition as shown in dotted lines in FIG. 13.

As an alternative and/or supplement, a selector can be used fordirecting heated exhaust gas from the exhaust system of the engine 30into the pipe 192. This is shown schematically. and it is to beunderstood that the blower can be disengaged, or left off entirely, andonly the exhaust system unit utilized for heated dry air if desired.Likewise, the exhaust system can be left out of the pipe circuitentirely if desired and only the blower 191 utilized.

The exhaust pipe 202 of the engine 30 is made so that it normally has anoutwardly extending portion 203 that connects to a suitable muffler ifdesired, or is merely discharged to atmosphere. Between the engine andthe outwardly extending end of the exhaust pipe a selector valveassembly illustrated generally at 204 is provided. The selector valveassembly, as shown perhaps best in FIG. 12, has a flapper valve 205operated by a lever 206 which can pivot about an axis and is movablebetween two positions. A drying gas pipe 207 is connected to pipe 202and also to pipe 192. The flapper valve will move between two positions,one wherein it blocks off exhaust pipe 203 and leaves pipe 207 open, anda second position wherein it blocks off pipe 207 and leaves pipe 203open.

When the use of exhaust gas as a drying medium is desired, for exampleif the heated gas from the exhaust is necessary to provide a drysurface, the belt drive 190 may be disengaged so that the blower is notoperating and the blower blades of course will substantially block theoutlet to the blower 191. This then will permit the moving of the valvelever 206 to its solid line position wherein the flapper 205 blockes offthe pipe 203 and the exhaust gases are forced into the pipe 207 and thenthrough the pipe system 192, 193, 194, 195, I97 and 198. This means thathot air will be blown down onto the surface 35 ahead of the wheelsthrough the nozzles 195A and 196A and 198A if additional air is desired,or a mixing of the air is desired, the belt drive can be engaged and theblower also utilized. This will create some back pressure on the valvesof the engine, but the blower pressure 191 will not have to be highbecause of the open pipe system leading to the nozzles that direct theblasts of air down onto the surface.

In the usual instance, either the exhaust air or the blower air will beutilized, but in some instances they can be intermixed.

This permits the drying of the surface 35 if it has been previouslywetted by being flooded, or if it is wet prior to the scrubbingoperation.

A feature, of course, is that the scrubber unit, including the spreaderpipe for the scrubbing liquid, whether it be detergent solution orwater, is trailing the drive and steering wheels of the power unit sothat they will normally operate on a dry surface unless the surface 35has previously been flooded or wetted. With the attach ments of thepresent invention, namely the nozzles directing air blasts ahead of thedrive and steering wheels, the unit can still operate on a dry surfaceeven though it has previously been flooded, and the surface willsubsequently be scrubbed to remove any streaks caused by the drying airand the power unit wheels.

Referring to FIG. 14, a modification of the present invention is shownwherein the scrubber unit can be made with a debris hopper positionedahead of the forward brush in relation to the direction of travel. Thescrubber unit can be made substantially similar as in the previous formof the invention, and the frame 215 is the same as frame 41 inconstruction extending transversely with respect to the direction oftravel, and the frame mounts brushes 216 and 217 for rotation indirection as indicated by the arrows 218 and 219. [n this instance,however, the unit is moving in direction as indicated by the arrow 220so that a dirt receptacle or hopper 221 is mounted ahead of the brush217, which in this case would be the leading brush.

The scrubbing unit can either be a trailing unit or a forward pushedunit (which is the form shown) in this instance, and as shown, a mast222 has a link 223 that is a push link attached to a power drive andsteering unit such as unit 12. The push link is pivotally mounted on thepower drive and steering unit and lifted and lowered with a cylindersuch as cylinder 95. Control links 224 to keep the scrubbing unit inproper position are also included. The hopper 221 is constructed withthe dump bottom as described in connection with FIGS. 9 and 8. Thebottom and links are numbered as explained in connection with FIGS. 8and 9. Other types of dumping could be used if desired, or a manuallyremovable receptacle could also be used.

The brushes 216 and 217 are driven by hydraulic motors, and mounted witha removable frame member 225 which corresponds to the frame member 44 inthe previous forms of the invention. The brush mountings would be thesame as before. The brushes would be rotated so that the deflector inthis instance 226 would deflect large debris forwardly into the hopper221, and a vacuum tube 227 would be used for removing any liquid thatwent into the debris hopper 221.

A secondary debris receptacle 230 is removably mounted just behind therear brush 216 as well, if desired, and as an opeional feature this alsowould have a vacuum tube 231 connected to a source of vacuum aspreviously explained to remove any dirty liquid that would get into thedebris receptacle. This receptacle 230 can be smaller than the mainreceptacle which in this instance is positioned ahead of the brushes.

A squeegee assembly 232 corresponding to the rear squeegee assembly 70is also mounted at the rear of the scrubber unit to wipe up any of theexcess liquid, and to remove it with a suitable vacuum hose in the usualmanner.

Thus, it can be seen that the debris receptacle 221 can be positionedahead of or to the rear of the double brush scrubbing unit, and thebaffle 226 can be positioned to give the desired direction of debristhrow. Further, the brushes 216 and 217 can be run at different speeds,as can the brushes 46 and 45. This will change the trajectory of theswept material.

A scrubbing liquid spreader pipe 233 is mounted on the frame 215adjacent the leading portions ahead of the forward brush 217 when lookedat in relation to the direction of travel, and this liquid spreader pipewill take scrubbing liquid from a scrubbing liquid solution tank on thepower unit used and distribute the liquid onto the surface 234 that isbeing scrubbed.

In FIG. IS, a simplified showing of a scrubbing unit illustratedgenerally at 240 is shown, to show that scrub brushes of different sizescan be used. Here, the frame 241 has a removable debris hopper 242 thatis mounted at the trailing end of the scrubbing unit, and suitable meanscan be used for removing it. As shown, the hopper will lift out of theframe. In this particular instance, the frame 241 mounts a pair ofbrushes, namely a large diameter brush 243, and a smaller diameter brush244 about parallel axes for rotation as indicated by the direction ofarrows 245 and 246. The brushes are driven with hydraulic motors mountedas previously described, and at the idler end of the brushes they aremounted on removable frame member 247 which corresponds to the removablemember previously mentioned. In this instance, a divider guide andbaffle 248 is mounted to direct debris into the debris hopper 242, and aportion of the scrubbing liquid will be carried over the forward brushand reused. A squeegee assembly is utilized on the trailing end of thescrubber, and on the sides thereof as shown in previous forms of theinvention. In this particular instance, the debris will go over thesmall brush, and the trajectory from the large brush will help to guidethe debris over as will the deflector or guide member 248. The unit caneither be a trailing or a push unit if desired, using suitable mountingmembers which are not shown to the separate power unit 11.

These brushes also usually will be rotating at different speeds. Theoptimum relationship between brush sizes has been found to be :4 whichmeans that a inch diameter brush 243 would use an 8 inch diameter brush244, and speed ratios is about 2:3 in rpm. is found to be satisfactory.For example, if the brush 243, the larger diameter brush, is travelingat 600 r.p.m., the small diameter brush 244 would traveling at 900r.p.m. This would make the peripheral speed of the small brush greaterthan the peripheral speed of the large brush, and this aids in carryingdebris over into the hopper. The large brush tends to throw materialupwardly and over the small brush.

The different diameter brushes can be used in the double brush scrubbingunit, and different brush speeds can also be used. The positioning ofthe hopper, whether it be ahead ofor trailing the brushes in relation tothe direction of movement, is not of critical importance, but in theinstance where a small brush and a large brush are used, the small brushshould be adjacent the hopper lip, as shown at 250. Here again, thehopper 242 can be removable manually with suitable handles right out ofthe frame 241 and the frame, of course, is constructed as previouslyexplained. The brushes extend transversely across the frame to get thedesired brush width, and the movement of the scrubbing unit can be ineither direction. As described, the hopper is trailing. The scrubbingunit will be supported by the power unit I1 and the power unit wouldhold the spreader pipe for applying a scrubbing liquid.

The separate scrubbing unit and power, drive and steering unit areeasily made into a front mounted scrubber. The pull link 88 would becomea push link and the drag links also could be used in compression. Thescrubbing unit could be raised or lowered with a hydraulic cylinder asdesired.

The present device has the ability to operate on smooth or roughsurfaces, as the double brush will clean rough surfaces well.

The solenoid valves used for operating the cylinder 164 for automaticpositioning of the scrubbing unit operate with suitable power sourcessuch as the vehicle battery. Also, the valves are four-way valves andare shown only schematically with pressure sources shown schematically.

The fourway valves have neutral positions that block off the ports tocylinder 164 so other valves can actuate the cylinder 164 in parallel.

what is claimed is:

l. A scrubbing machine for scrubbing a surface comprising a frame, apair of surface engaging rotary tools mounted on the frame for rotationabout parallel, transversely extending axes, means on the frame forapplying a scrubbing liquid to the surface in the path of movement ofthe rotary tools over the surface, and means mounted on the frame forcollecting scrubbing liquid, the last mentioned means including squeegeemeans along the lateral sides of the frame laterally aligned with saidrotary tools, said squeegee means ineluding surface engaging row brusheson each side of the frame adjacent the ends of the rotary tools andaligned with the gaps between the rotary tools, said squeegee meansfurther including a squeegee frame ex tending along one lateral side ofthe frame, one of the row brushes being mounted on the squeegee frame,and a flexible surface engaging member mounted on the squeegee framelaterally outwardly of said one row brush from the rotary tools andextending fore and aft of the rotary tools.

2. The apparatus of claim 1 further characterized in that the rotarytools are rotary brushes, that the one row brush is attached to thesqueegee frame to extend inwardly toward the rotary brushes and engagethe surface close to the ends of the rotary brushes, and that theflexible members are slanted outwardly with reference to the squeegeeframe.

3. A scrubbing machine for scrubbing a surface comprising a frame, apair of surface engaging rotary tools mounted on the frame for rotationabout parallel, transversely extending axes, means on the frame forapplying a scrubbing liquid to the surface in the path of movement ofthe rotary tools over the surface, and

1. A scrubbing machine for scrubbing a surface comprising a frame, a pair of surface engaging rotary tools mounted on the frame for rotation about parallel, transversely extending axes, means on the frame for applying a scrubbing liquid to the surface in the path of movement of the rotary tools over the surface, and means mounted on the frame for collecting scrubbing liquid, the last mentioned means including squeegee means along the lateral sides of the frame laterally aligned with said rotary tools, said squeegee means including surface engaging row brushes on each side of the frame adjacent the ends of the rotary tools and aligned with the gaps between the rotary tools, said squeegee means further including a squeegee frame extending along one lateral side of the frame, one of the row brushes being mounted on the squeegee frame, and a flexible surface engaging member mounted on the squeegee frame laterally outwardly of said one row brush from the rotary tools and extending fore and aft of the rotary tools.
 2. The apparatus of claim 1 further characterized in that the rotary tools are rotary brushes, that the one row brush is attached to the squeegee frame to extend inwardly toward the rotary brushes and engage the surface close to the ends of the rotary brushes, and that the flexible members are slanted outwardly with reference to the squeegee frame.
 3. A scrubbing machine for scrubbing a surface comprising a frame, a pair of surface engaging rotary tools mounted on the frame for rotation about parallel, transversely extending axes, means on the frame for applying a scrubbing liquid to the surface in the path of movement of the rotary tools over the surface, and means mounted on the frame for collecting scrubbing liquid, the last mentioned means including squeegee means along the lateral sides of the frame laterally aligned with said rotary tools, said squeegee means including surface engaging row brushes on each side of the frame adjacent the ends of the rotary tools and aligned with the gaps between the rotary tools, said squeegee means also including separate lateral side squeegee assemblies adjacent each side of the frame and to the outside ends of the tools, each of the side squeegee assemblies having one of said row brushes and a flexible surface engaging member on the opposite side of the row brush from the rotary tools, and a rear squeegee assembly extending transversely for substantially the axial length of the rotary tools and having forwardly extending portions adjacent the lateral, sides thereof, said side squeegee assemblies having trailing end portions overlapping the respective forwardly directed portions of the rear squeegee assembly and positioned on the inside of the forwardly directed portions, means for mounting the side squeegee assemblies to the frame, and means for mounting the rear squeegee assembly on the frame.
 4. The scrubbing machine of claim 3 further characterized in that the side squeegee mounting means includes leaf spring means for each side squeegee assembly for mounting the respective side squeegee assembly on the frame and resiliently urge it against the surface and that the rear squeegee mounting means inCludes parallel arm means pivotally mounted on the frame and pivotally connected to the frame for mounting the rear squeegee assembly for limited movement toward and away from the frame, and fluid actuated cylinder means mounted on the frame for selectively moving the rear squeegee assembly toward and away from the surface being maintained.
 5. A surface maintenance device comprising a framework forming a housing, a pair of rotatable surface engaging maintenance tools rotatably mounted within said housing about substantially parallel spaced apart axes which are parallel to the surface to be maintained, power means to rotate said maintenance tools in opposite direction wherein said tools rotate toward each other when in contact with said surface, a receptacle to receive material carried by said maintenance tools, means to determine the path of material carried by said maintenance tools to deflect debris from the surface being maintained toward said receptacle, and permit a portion of any liquid picked up by said tools to move in opposite direction from said receptacle, means for applying a liquid scrubbing solution to the surface over which said tools are moved, and squeegee means for collecting scrubbing liquid, said squeegee means including a squeegee member adjacent each of the side edges of said housing, each squeegee member including a squeegee frame extending across the transverse gap between the tools, row brush means attached to said squeegee frame, said row brush means being positioned adjacent the rotating tools and aligned with the transverse gap between the tools, and a flexible surface engaging member mounted on the squeegee frame to extend therealong outwardly of said row brush means from the rotary tools across the transverse gap between said rotary tools.
 6. The apparatus of claim 5 further characterized in that said squeegee means includes a rear squeegee assembly, means mounting the rear squeegee assembly for selective movement toward and away from the surface being scrubbed, fluid pressure means to control movement of the rear squeegee assembly and control means for said fluid pressure means to limit the amount of downward force on said rear squeegee assembly.
 7. In a scrubbing machine for a surface, said machine having a frame, scrubbing means mounted on said frame, scrubbing liquid application means, and means to retrieve scrubbing liquid subsequent to its use by said scrubbing means, the improvement comprising squeegee means along the lateral sides of said frame laterally aligned with said scrubbing means, said squeegee means including flexible surface engaging means, and leaf spring means mounting said squeegee means to said frame to resiliently urge said flexible surface engaging means against said surface.
 8. The scrubbing machine of claim 7 further characterized in that said scrubbing means comprises a pair of brushes rotatably mounted about parallel transversely extending axes, and row brush means attached to said squeegee means, said row brush means being positioned on each side of the scrubbing unit adjacent the ends of the rotating brushes and aligned with the gap between the brushes.
 9. A surface scrubbing machine having a frame member, means to move said machine along the surface to be scrubbed, a pair of counterrotating scrubbing brushes rotatably mounted on said frame member about substantially parallel axes substantially transverse to the direction of movement of said scrubbing unit, means to apply a liquid scrubbing material in the path of normal travel of said scrubbing brushes, a trash receptacle adjacent a first one of said brushes, means to direct solid debris and a first portion of the liquid scrubbing material engaged by said brushes over said first one of said brushes into said receptacle, means to cause recirculation of a portion of the liquid scrubbing material picked up by said brushes back onto the surface being scrubbed in the path of travel of said brushes, a first squeegee assembly, means mounting said squEegee assembly to the rear of both of said brushes in respect to the direction of travel, said squeegee assembly extending transversely for substantially the axial length of said brushes, and having forwardly extending portions adjacent the lateral sides thereof, and separate lateral side squeegee assemblies adjacent each side of said frame member and to the outside of the ends of said brushes, said side squeegee assemblies having trailing end portions overlapping the respective forwardly directed portions of said first squeegee assembly and positioned on the inside of said forwardly directed portions.
 10. A surface scrubbing machine having a frame member, means to move said machine along the surface to be scrubbed, a pair of counterrotating scrubbing brushes rotatably mounted on said frame member about substantially parallel axes substantially transverse to the direction of movement of said scrubbing unit, means to apply a liquid scrubbing material in the path of normal travel of said scrubbing brushes, a trash receptacle adjacent a first one of said brushes, means to direct solid debris and a first portion of the liquid scrubbing material engaged by said brushes over said first one of said brushes into said receptacle, means to cause recirculation of a portion of the liquid scrubbing material picked up by said brushes back onto the surface being scrubbed in the path of travel of travel of said brushes, and a squeegee assembly to the rear of said brushes, means to mount said squeegee assembly on said frame comprising pivoting parallel arm means, and means to raise said squeegee assembly off the surface being scrubbed.
 11. The apparatus of claim 10 further characterized in that the means to raised the squeegee assembly comprises fluid actuated cylinder means mounted on the frame for selectively moving the squeegee assembly toward and away from the surface being maintained.
 12. A surface scrubbing machine having a normal direction of forward movement and comprising a frame, means to move said machine along the surface to be scrubbed, a scrub brush mounted on said frame, means to apply a liquid scrubbing material in the path of normal travel of said scrub brush, a squeegee assembly to the rear of said brush, and means to mount the squeegee assembly on said frame for selective movement toward and away from the surface being scrubbed, the last mentioned means including a pair of parallel arms pivotally connected to the frame and to the squeegee assembly, the fluid actuated means for selectively moving the squeegee assembly toward and away from the surface being scrubbed and applying a downward force on the squeegee assembly.
 13. The apparatus of claim 12 further characterized in that there is provided control means for the fluid actuated means to limit the amount of downward force applied to the squeegee assembly.
 14. A scrubbing machine for scrubbing a surface comprising a frame, rotary brush means mounted on the frame for scrubbingly engaging said surface, means on the frame for applying a scrubbing liquid to the surface in the path of movement of the brush means over the surface, and means mounted on the frame for collecting scrubbing liquid, the last mentioned means including squeegee means, said squeegee means including a row brush, a flexible surface engaging member, and a squeegee frame mounting the row brush adjacent the brush means and mounting the flexible member on the opposite side of the row brush from the brush means. 